Conventionally, in order to improve running safety of a railway vehicle, online real-time monitoring for detecting an abnormality of a commercial vehicle (a railway vehicle in commercial operation) while the commercial vehicle is running has been performed with various sensors attached to the commercial vehicle by monitoring a state of the commercial vehicle running on a commercial line by the sensors (for example, see Patent Literatures 1 and 2).
However, to detect the abnormality of the running vehicle using the above method, the sensors need to be attached to all vehicles, and maintenance and inspection of the sensors are time-consuming. Therefore, the problems are that the vehicle abnormality cannot be easily detected, and it costs a lot.